Dry spun and dry cast structures of synthetic materials



Patented May 29, 1945 DRY SPUN AND DRY CAST STRUCTURES OF SYNTHETIC MATERIALS Paul W. Morgan, Kenmore, N. Y.," assignor to E. I. du Pont de Nemours & Company, Wilmington, Del., a corporation of Delaware No Drawing. Application December 5, 1942, Serial No. 467,933

6 Claims. (CI. 18-54) This invention relates to the manufacture'of products such as filaments, yarns, ribbons. and films comprised of synthetic polymeric material.

More particularly, it relates to the improvementv in the dyeing characteristics of filaments, yarns, ribbons, films and th like made by the dry or evaporative spinning or casting of synthetic 111mand filament-forming, water-insensitive, synthetic polymeric materials such as cellulose esters, cellulose ethers, polyvinyl acetals, polystyrenes, methacrylate polymers, etc.

Products resulting from the dry spinning or dry casting of synthetic polymeric materials, particularly the cellulose organic derivatives such as cellulose acetate, cellulose propionate, cellulose butyrate, methyl cellulose, ethyl cellulose, and mixed cellulose esters, ethers and ester-ethers,

which are water-insensitive, i. e. do not swell appreciably in water, have little or no amnity for direct dyes commonly'used in dyeing cotton and regenerated cellulose, or for acid and chrome dyes commonly used to dye wool.

This fact is of especial concern in the textile field because the dyes which do satisfactorily dye these synthetic polymer materials do not dye cotton, wool or regenerated cellulose, and where,

as is often the case, one of the water-insensitive synthetic polymer materials is combined with wool, cotton or regenerated cellulose to form a mixed fabric, uniform dyeing of such fabric is a desideratum difficult to realize even by using two which operate to prevent collapse of the cell walls,

- and those which involve incorporation in the filament structure of substances such as basic nitrogen-containing,compounds which operate as dye acceptors,.have shown considerable promise. In practice these substances are added to the filamentor film-forming solutions. However, ex-

perience has shown that in yarnsfornied by the dry spinning technique, inert substances in amounts of the order of 75% to 100% or more, based on the weight of cellulose acetate, must be contained in the formed filaments in order to achieve satisfactory dye receptivity. Such a high percentage of inert material serves to so weaken the yarn during processing that it is of reduced commercial value. Dry spun yarns of cellulose acetate containing only basic nitrogen-containing compounds in amounts of the order of 5. to 20% may be dyed deeply and uniformly but the fastness of such dyeings to light is generally poor.

In order to overcome to some extent the limitation attending dry spun yarns containing a very high percentage of awater-soluble substance, it

dye baths, one for dyeing the water-insensitive synthetic polymeric material and one for the natural fibers. Furthermore, the dyes and dyeing, processes useful in the coloring of the waterinsensitive synthetic polymers are very costly in comparison with the acid, direct, and chrome dyeing of natural and artificial textile materials.

It is therefore desirable that the dyeing afilnities of organic derivatives of cellulose and like filmand filament-forming materials bemodifled to. render them susceptible to satisfactory dyeing with acid, direct and chrome dyes. A great number of expedients for the purpose,'heretofore employed, involve chemical modification of the polymer to a point where wanted characteristics are often sacrificed. Other expedients efl'ect only physical modification and are based on the well known fact that the yarn, e. g. cellulose acetate yarn, is readily dyed while in the gel state,'i. e. before the cell walls of the filaments thereof have collapsed and formed abarrier against penetration of the dye solution. Of these latter prohas been further proposed to after-treat the yarn in one'or more aqueous baths to dissolve out the inert substance and to replace it by a very 50% of the polymeric filamentor film-forming posals those which involve incorporation in the filament structure of soluble inert substances substance, consists in the neighborhood of or of the polymeric product and because of this substantial replacement of the bulk agent and condensation of the structure prior to forming it into fabrics, generally improved fabrics can thus be produced. The carrying out of this process, however, is necessarily expensive in view of the time and equipment needed to satisfactorily after-treat the formed filaments.

I have now found that, in spite of all the difficulties arising from prior methods of altering the amnity for water-insensitive synthetic polymeric structures to accept acid, direct and chrome dyestuffs, a certain combination of these prior proposals, when properly combined, will enable cellulose organic derivative yarns, ribbons, films and the like, and structures of other water-in sensitive synthetic polymers to be produced which have good aillnity for acid, direct and chrome dyestuffs, which dyeings will be reasonably fast to 55 washing and light fading.

1 with acid, direct and chrome dyes;

A further object is to provide a process for con-i i ferring on dry spun or caststruc'tures of waterinsensitive filamentor film-forming synthetic polymers, affinity for acidgdirect and chrome dyes. A still further object is to form dry spun yarns 1 of cellulose organic derivatives which can be dyed 3 These and other objects will more 1 pear hereinafter. v v 7 These objects are accomplished by my invention which comprises incorporating in a spinning clearly apwithin the filament structure.

The amount of bulk agent incorporated in the spinning Or casting liquid may range from about 10% toiabout 60% of the amount of the cellulose acetate in the spinning liquid. In itself, thisamount of agent would not give-to the yarn or other structure produced from such a solution any substantial affinity for acid, direct or chrome dyestufis. However, when used in combination with from about 0.5%to about 10% of a basic trivalent i nitrogen-containing compound, based 'on the cellulose acetate, such one compound containing 3 or casting liquid fromwhich structures of water: a 3

\insensitive filament-or film-forming synthetic polymers are formed, mutually compatible con- 1 stituents'comprising (1) a bull; agent soluble in amino nitrogen, the structure formed therefrom bythe dry or evaporative method may. subse quently be dyed to full shade with any of the w common acid, direct or chrome dyestufls. Again,

if thebasic trivalent nitrogen compound were used alone and only in the concentrations needed 1 the spinning or casting liquid and also soluble in 1 a convenient after-treating liquid which is not a .j

g solvent for said po1ymers,and (2). a substance containing basic trivalent nitrogen, also soluble? in the spinning or castingliquid. The filament or film is formed in the usual way by the dry or 1 evaporative method, and the bulk agent, is sub- 3 sequently removed just prior to or during the ,dye- 5 ing operation, by the action of the after-treating 1 liquid'in which the bulk agent is soluble.

7 'By' the term bulk agent is meant any'relaall t tively nonvolatile inert impre'gnant which can fill j the capillaries or. spaces between molecules or crystallites of the synthetic polymer and prevent l-substa ntial collapse of the walls enclosing these :.y V

filtering, the solution was spun by an electrical spaces on drying of the filament 0r film.

As a matter of convenience, the invention will i or film-forming synthetic polymer, it being underbe further described with specific reference to l 1' cellulose acetate as thewater-insensitive filamentl stood that the invention is applicable as well to j all members of the broad class heretofore'depurposes of this invention. 1

, Representative suitable compounds containing j basic trivalent'nitrogenfor combining with the bulk agent in the solution are tetraethylene pentamine, Hyamine HC-(a nitrogenous basic v amine polymers such as deacetylated chitin,

hexylaminoethyl methacrylate polymer, the reaci dlmethylaminethe reaction product of tertiary amyl phenol, formaldehyde and dimethylamlne,

or in aqueous'scouring liquid prior'to dyeing must substance marketed by 'Rohm and Haas 'Co.), phenol -f0rmaldehyde-aminocaproic acid resin,

dimethylaminoethyl methacrylate polymer, di-f ethylaminoethyl methaprylate polymer, hexose Glycol polyformal (molecular weight from 400 to 1000) constitutes the preferred bulk agent for -piperidyLN-ethyl methacrylate polymer, dicycloj tion product of meta-cresol, formaldehyde and diethanol methylamine succ'inate condensation polymer and diethanol methylamine ,phthalate 1 condensation polymer. While most of these compounds are water-insoluble, some few of them,

of course be avoided, since prolonged soaking or scouring before dyeing would result in leaching out of the dye acceptor compound from the yarn,

beforethedye acceptor has reacted with the dye n for the'purposes of this invention, then the struc- I ture produced therefrom would also. lack sumcient aflinity for direct, acid and chrome dyestuffs to permit dyeing to full-shades. The following examples further invention. Parts are by weight.

Example I 'A cellulose acetate spinning solution was pre pared by dissolving 12 parts of cellulose acetate (containing about 54.5% combined acetic acid) in 90 parts of acetone and to this solution was added 0.10 part of tetraethylene pentamine and. 3.0 parts 'of glycol polyformal (molecular weight 463). After thoroughly mixing, deaerating and spinning process such as described in U. S. Patent No. 1,975,504 (Formhals) to produce discontinuous fibers. These fibers were of good quality and contained about 0.8% tetraethylene pentamine and about 25% glycol polyfcrmal, based on the cellulose acetate. Deep, uniform and fast ,dyeings were obtained with a number of direct, acid and chrome dyestuffs including Pontamine Fast Y Red 8BL, Pontacyl Carmine 2G, Pontacyl Light Yellow G'X, Pontacyl Violet RL, fPontac'yl Carmine 2B,"Du Pent Anthraquinone Blue.

SWF, Du Pont Orange G, 'Du Pont'Brilliaht Milling Blue B, Du Pont Brilliant Milling Green B, Du .Pont Milling Yellow GN,'and P ontachrome" Azure ,Blue B.

' Example I A solution comprised of 22.2 parts 0 acetonesoluble cellulose acetate, 80' parts of a etone, 7.5

parts of glycol polyformal (425 molecular weight), and 0.3 part of dimethylaminoethyl methacrylate polymer was dry cast'on a plate to form a film. This film had good aifinity fortypical acid and direct dyestufls. When the amount of dimethylaminoethyl methacrylate polymer was increased to 0.6 part, the other ingredients of the solution remaining the same, a film which dyed to full deep shades with acid and direct dyestuffs was obtained. In the absence of glycol polyformal in the filnr and'even though the concentration of dmethylaminoethyl methacrylate polymer therein was 21%, films thus produced showed very little "dye afilnity for the acid and direct dyestuffs.

Likewise films containing 1 part of glycol poly formaltos parts of cellulose acetate and no dye acceptor; showed very little dye affinity, and not until th'e' a mount of glycol polyformal was inc.eased-to,equal parts with the cellulose acetate -(wlth'out a dye acceptor) could excellent dye whereby to form an insoluble color compound illustrate the afiinity for acid, direct and chrome dyestufls be obtained.

Although this invention has been specifically described in terms of producing cellulose acetate structures of the acetone-soluble type, it is also applicable to the modification of cellulose acetates of other combined acetic acid values; such as substantially completely acetylated celluose, commony termed cellulose triacetate. The invention is also applicable to other cellulose esters, such as cellulose propionate, cellulose butyrate, mixed esters such as cellulose acetate butyrate, cellulose acetate propionate and the like; cellulose ethers such as methyl cellulose, ethyl cellulose, benzyl cellulose, mixed ethers such as methyl benzyl cellulose, mixed ether esters such as'ethyl cellulose acetate, and other similar organic derivatives of cellulose which are organic solvent-soluble. Furthermore, other water-insensitive polymeric filamentor film-forming materials may be modified in accordance with this invention; for instance, polyvinyl acetals and other polyvinyl products, polystyrene, methacrylate polymers and the like.

In addition to improving the dye receptivity of dry spun ordry cast structures of water-insensitive synthetic polymers, the present invention can be employed with advantage to facilitate incorporation in such structures of plasticizers, resins, resin-forming ingredients, lubricants or any other of the agents commonly employed'to improve and modify the characteristics of yarns, films and the like. For example, the desired agent is most conveniently and efiectively introduced into the structure while it isstill in a porous condition, i. e. immediately after the bulk agent has been removed and before the resultant porosity is substantially reduced by drying.

Structures of water-insensitive filament and film-forming synthetic polymers are modified in accordance with this invention without substantial sacrifice of essential physical properties; tenacity, for instance, being at least one gram per denier in the case of modified filaments and fibers of cellulose acetate. Also, the volume shrinkage due to the elimination of the bulk agent by aftertreatment prior to dyeing is not excessive as in the case 01 prior art treatments involving the use of bulk agents. Furthermore, because of the relatively small amount of basic trivalent nitrogen compounds present, the dyed structures are not subject to excessive fading when exposed to sunlight and yet have excellent afiinity for acid, direct and chrome dyes.

I claim:

1. In the process wherein filaments, yarns, ribbons, films, and like structures are formed by the dry or evaporative method from a liquid containing a water-insensitive filamentand film-forming synthetic polymeric material and thereafter dyed, the improvement which comprises adding to said liquid (1) from about 10% to about 60%- by weight, based on the weight of said polymer, of glycol polyiormal (molecular weight from 400 to 1000), and (2) from about 0.5% to about 10% by weight of a basic trivalent nitrogen-containing compound soluble in said liquid, whereby said structures are rendered receptive to direct, acid and chrome dyes.

2. In the process wherein filaments, yarns, ribbons, films, and like structures are formed by the dry or evaporative method from a liquidcontaining a cellulose organic ester and thereafter dyed,

, the improvement which comprises adding to said 4o yarns, ribbons, films, and like structures comganic ester, of glycol polyformal liquid (1) from about 10% to about 60% by weight, based on the weight of said cellulose or- (molecular weight from 400 to 1000), and (2) from about 0.5% to about 10% by weight of a basic trivalent nitrogen-containing compound soluble in said liquid, whereby said structures are rendered receptive to direct, acid and chrome dyes.

3. In the process wherein filaments, yarns, ribbons, films, andlike structures of cellulose acetate are formed by the dry or evaporative method from a solution of cellulose acetate in an organic solvent, the improvement which comprises adding to said solution from about 10% to about 60% by prised essentially of (1) water-insensitive fila-.

mentand film-forming synthetic polymeric material, (2) from about 10%t0 about 60% by weight, based on the weight of said polymer, of glycol polyformal (molecular weight from 400 to 1000), and (3) from about 0.5% to about 10% by weight of a basic trivalent nitrogen-containing compound, said structures having an ailinity for'acid, direct and chrome dyes.

6. As new articles of manufacture filaments, yarns, ribbons, films, and like structures com'- prised essentially of (1) cellulose acetate, (2)' about 10% to about 60% by weight, based on the weight of cellulose acetate, of glycol polyi'ormal (molecular weight from 400 to 1000), and (3) from about 0.5% to about 10% by weight of tetraethylene pentamine, said structures having an afllnity for acid, direct and chrome dyes.

PAUL W. MORGAN. 

